Yes, there are rather many of them, however this sphere is still developing and I suppose that in future there will be a much greater amount of them, also with a better quality. They're used now for many purposes, the main one is checking various aspects of your body state, like pulse, weight and so on, such type of these apps is the most popular among average users. There are also special ones for getting patients to the right specialists, providing an easier access to patient portal idapgroup.com/blog/healthcare-mobile-app-development-future-hospital/ , losing weight and so on. In which certain ones are you interested?
In case of Android in general I can recommend you CareZone, Doctor on Demand, Epocrates, mySugr, Weather Underground and so on. All of them are rather simple for using and aren't very expensive.